Investigators also booked Aguilar on Sunday with DWI, his seventh arrest for drunk driving in Louisiana since 1992, authorities said. Charges in the most recent case, a Dec. 5, 2011, DWI-fourth offense arrest, are pending in Jefferson's 24th Judicial District Court, McGregor said.

Now, Aguilar is accused of injuring the driver of another vehicle and her pregnant, 18-year-old passenger. The accident occurred Sunday about 6:46 p.m. at the intersection of Alabama Avenue and Vintage Drive, McGregor said.

A witness spotted Aguilar's Chevrolet Silverado pickup truck traveling northbound in the 3800 block of Chateau Boulevard. But Aguilar was in the wrong lanes of travel on the thoroughfare, which is divided by a median.

The witness followed Aguilar as he made a right turn onto Vintage Drive. The truck was back in the proper lanes of travel. But when Aguilar made a left turn onto Alabama Avenue, he proceeded through a stop sign and pulled in front of a Mitsubishi Galant that was headed westbound on Vintage, according to McGregor. "They basically T-boned him," he said.

The driver suffered cuts to her right hand and knee. Authorities took her pregnant passenger to a local hospital after she complained of abdominal pain, McGregor said.

Doctors later learned that the mother, who was seven months pregnant, suffered a lacerated uterus, and the baby died. The mother was in critical condition Monday after doctors performed surgery, McGregor said.

Aguilar was still being held Monday without bond at the Jefferson Parish Correctional Center in Gretna. Anyone with information about the case is asked to contact the Kenner Police Department by calling 504.712.2222 or Crimestoppers at 504.822.1111.

Stay with NOLA.com for more information about this story as it becomes available.